Safety Review Exercises

1.11 Safety Review Exercises

         i.            List six items of protective clothing and state where each is used.

       ii.            Distinguish between a face shield and a helmet.

      iii.            List three methods of storing tools.

     iv.            List four possible causes of electric shocks.

       v.            Why should first aid be administered?

     vi.            State conditions necessary for fire to commence.

    vii.            Explain how one can extinguish an electric fire.

  viii.            Where would you place a fire extinguisher at home?  State reason for your selection.

     ix.            Give reasons for not taking shelter under a tree when it is raining.

Safety Key Points

1.10 Safety Key Points

1.       In order to enjoy work and play we must think of our safety and that of others.
2.       Avoid fooling and horse play. There is no fun when you or someone else is hurt.
3.       Dress for safety.
4.       Keep work places and passages clean and clear of unnecessary tools, equipment and materials.
5.       Stores tools, equipment and materials in their properly designed places for safety.
6.       Stores should be well ventilated and lit.
7.       Be familiar with first-aid procedures. Your skills may save the life of a friend.
8.       Be familiar with the position and operation of firefighting equipment.
9. Remember fire extinguisher fighting acronym P.A.S.S. for effective application. It stands for: Pull, Aim, Squeeze, Sweep; meaning:
a. Pull the safety pin from the handle. The pin is positioned at the top of the fire extinguisher. When detached, it releases the locking mechanism and allows discharge the extinguisher.
b. Aim the fire extinguisher nozzle at the base of the fire.
c. Squeeze the lever gently to discharge the reagent.
d. Sweep side to side roughly 15cm or half a foot over the fire until depleted.

10.       Make sure the electric circuits are safe before energizing them.
11.       Never panic in an emergency: This is when you need your reasoning most.

Lightning Source

Lightning Source

Lightning occurs in many parts of the country, usually during the rain seasons. Sometimes it causes death to people and animals, and destroys trees and buildings. Some understanding of the nature of lightning will be of help when dealing with related safety precautions.

The friction between a rising, warm air mass and a falling, cold mass causes the air masses to be electrically charged. In order to rid of the charge, that is to discharge, a large spark flashes between them. This flash of light is the lightning. The heat caused thereby heats the air suddenly, causing it to expand with a loud sound. This sound is the thunder. Thunder and lightning occur simultaneously. But since light travels faster than sound, lightning is seen before thunder is heard.

Sometimes the warm and cold air masses get charged very close to the earth. The mass closest to the earth discharges towards the earth. In this ease the lightning strikes the earth. It appears very bright and the thunder is very loud. A human being, animal, tree or building, found in the path of lightning will be struck. When this happens, the victim may receive a very severe electric shock or die; a tree or building may be destroyed and catch fire.

To avoid being struck by lightning, the following should be observed:

a.                   Avoid taking shelter under a tree when it is raining. Shelter in a building or a vehicle.

b.                  Never be the tallest “object” on a large, plain ground.

c.                   Install lightning arrestors (conductors) on all buildings.

d.                  Plant trees in clusters. They share the effect of lightning, acting as an arrestor.

High voltage power lines

1.9 High voltage power lines and Lightning

Electric accidents may occur to people even when they are not dealing directly with electricity. Two sources of such accidents are the high voltage power lines and lightning.

High voltage power lines

Two types of power lines are used: overhead power lines and underground power lines.

 Overhead Power Line

The power company distributes electricity throughout the country by overhead lines. The cables are not insulated. They are supported by tall posts called pylons to reduce the chances of people, animals and vegetation touching the bare conductors, since to do so may cause death.

The following safety precautions should be observed in order to avoid accidents from overhead power lines:

a.       Never attempt to climb electric power posts.

b.      Do not touch broken overhead cables. Warn others about it and report to the authorities.

c.       Avoid climbing trees near overhead power lines.

d.      Avoid felling trees near electric power lines.

e.      Do not throw objects at the power lines.

f.        Never erect buildings below power lines,

g.       Avoid setting fires near power line posts.

Underground Cables

In cities and towns, housing estates and farms, electricity may not be distributed safely by overhead cables. It is distributed by insulated cables buried underground. These are called underground cables. Serious accidents may occur if the cables are broken when one is digging the ground. To avoid such accidents, the following precautions should be observed:

a.       Study the electricity distribution in the area.

b.      Consult the underground cable layout plans to locate and mark the presence of underground cables.

Firefighting procedures

1.8 Firefighting procedures

Fire spreads fast. However, how quickly it is detected and controlled determines the extent of damage it causes. Once fire is detected, raise the fire alarm; act fast to put it out. If it is big, evacuate the building and call the fire brigade.
There are three classes of fire: Electrical, chemical and solid. Each class is controlled using appropriate firefighting equipment.

How to Control Electric Fires

Electric fires involve the burning of insulation of the conductors. The fire may spread to other combustible materials if not put out in good time. Some fundamental steps for fighting electric fires are:
1. Switch off the main electrical power supply.
2. Spray the burning material using carbon dioxide or dry powder extinguishers.

REMEMBER:
Water and foam extinguishers should never be used on electric fires.

How to Control Chemical Fires

Burning oil or chemical fires are controlled by spraying them with foam, carbon dioxide or dry powder extinguishers. Sand or soil may also be used by pouring either on the base of the fire.

How to Control Solid Fires

Solid fires include all types of burning wood and other materials. For these all types of fire extinguishers may be used although the water type is usually preferred. The fires may also be sprayed with water directly from water hoses or taps. Sand or soil is also used. Covering materials like blankets and twigs of trees are sometimes used to put out flames and, therefore, reduce the chances of the fire spreading.

Note:
The above procedures are only applicable to localised or small fires.  For big fires, firefighting companies or the government's municipal authorities must be called.

Firefighting Activity

I. Write a simple step-by-step protocol that articulates what you will do if you encounter an fire in the Chemistry Lab at school.
II. Make a cue card for your protocol that will fit in your wallet. If possible laminate it.

How to Use a Fire Extinguisher

How to Use a Fire Extinguisher

Fire extinguishers are handy and very easy to operate. There are different designs of them and each has its own ways of operation depending on the manufacturer. It is important to be familiar with the instructions printed on each design instead of waiting until fire breaks out, which generally are:

a.       Hold the extinguisher upright, then remove the safety pin or cap.

b.      Direct the nozzle to the base of the flame.

c.       Press the level or strike the knob.

d.      Spray the base of the fire.

After use fire extinguishers should be sent back to the manufacturer for refilling. They also need to be inspected regularly to ensure they will be effective when needed. Every workshop should have fire extinguishers. They should be placed in an easily accessible position, such as near the doors and where a fire is most likely to start.

Point to remember before attempting to put out fire

1. Call for higher authorities if fire is immense
2. Check that all people are out of the fire place and assembled at safe meeting place
3. Do not panic
4. Check for your safety to ensure exit points, toxic smoke emission, structural safety of the area like burning walls, roofs, etc.,
5. Your life is more important than fire "Think of your safety and those of others"
6. Use common sense; only small fires can be fought using fire extinguishers
7. Check the type of fire and type of extinguisher available

NB.
If the fire does not respond to fire extinguisher, take off to a safe distance because it is futile to expose yourself to risk without achievement.

Different types of fire extinguishers

1.7 Different types of fire extinguishers

Fire extinguishers are used to put out small fires. They are of different types with each made to deal with a specific class of fire. They are classified according to firefighting material in the equipment.  The following are the most commonly used:

Water Extinguishers

Usually used to put out fires on burning solid materials.

Foam Extinguishers

Used to put out fires on burning oils and chemicals.

Carbon Dioxide Extinguishers

Used to fight fires on burning gases or vapours.

Dry Powder Extinguishers

Used to deal with fires on burning, flammable liquids and some solids, such as wood and paper.

Water and foam are conductors of electricity. Therefore, they should never be used to fight electrical fires unless the supply of electricity is disconnected; carbon dioxide and dry powder extinguishers are recommended Instead.

Other Extinguishers

Besides the above commercially made fires extinguishers, sand, soil and other covering materials may be used to fight fires

First aid definition

1.6 First aid definition

First-aid is defined as the application of skilled principles in the event of a sudden illness or accidents by the use of the readily available facilities until the casualty is taken to the doctor for proper medical attention.

The importance of first-aid is to:

                                 i.            sustain life,

                               ii.            promote recovery,

                              iii.            prevent the situation from worsening.

The general systematic procedure to be observed when handling casualties involves:

1.       Switch off the current

2.       Secure release from contact; use non-conducting materials.

3.       Start artificial respiration if casualty is not breathing.

4.       Send for a doctor or an ambulance.

Treatment of Cuts

Wounds can result from:

a.       Bruises, that is, under-skin or surface injury.

b.      Minor cuts, that is, slight broken skins with some bleeding.

c.       Deep cuts, that is, a major broken skin and muscles with serious loss of blood.

The general procedure is to disinfect the affected part and apply the relevant pain and germ killing ointments. Thereafter, apply suitable dressing before taking the victim to a doctor.

In the case of a deep cut:

1.       Stop the cut from any further bleeding by applying a pad.

2.       Clean the cut and apply a suitable ointment.

3.       Take the casualty to a doctor.

Treatment of burns and scalds

Burns

Caused by dry heat from fire, hot objects or over exposure to the sun.

Scalds

Caused by fluid or moist heat (steam or vapour).

In both cases, the general treatments should be administered as per the prevailing conditions; but the common rules should be to:

1.       Place the affected part under a slowly running cold water or immerse in cool water as soon as possible.

2.       Remove any constrictions (rings, bangles, boots, etc.).

3.       Cover the affected part with a clean cloth.

4.       Immobilise the burned limbs.

5.       Give small quantities of cold drinks to the victim.

6.       Arrange for immediate transport to hospital.

Electrical Hazards

1.5 Electrical Hazards

In everyday's life we get reports of what how fires fires have caused havoc.  It is unfortunate t that when such is heard from learning institutions and heavy industries, investigations has always pointed to electric faults.
There are many causes of electrical hazards.   In an electric circuit two types of hazards are possible:

• electric shocks,
• electric fires.

1.51 Electric Shocks

Electric shocks are basically caused by:
1.       Poor Electric Circuit Conditions
These include old and worn out or improperly serviced electric circuits and appliances.
To prevent electric shocks, great care should be exercised to ensure that:
a.       the wires are always properly and firmly connected,
b.      they are properly insulated,
c.       worn out cables are replaced immediately,
d.      appliances are properly earthed.
2.       Carelessness
This is the act of overlooking safety procedures by:
a.       not paying attention to or following all the given instructions,
b.      being hasty in one’s work.

3.       Working under the influence of impairing drugs such as alcohol,
4.       Incompetence in handling electric circuits,
5.       Fatigue,
6.       Stress.

1.52 Electric fires

The three main causes of electric fires are:
1. Circuit overloading,
2. Arcing contacts,
3. Heating appliances within the proximity of combustible materials.
Fire starting from an electric circuit can be categorised as:
(a)          Those involving the insulation and contained within the appliance.
(b)          Those starting from within the appliance due to a short circuit or excessive current and spreading out to the area around as general fire.
In both cases, the fire is detrimental to life and property; proper techniques of firefighting must be devised to minimize losses.

Storage and Handling of Equipment

Storage and Handling of Equipment

In order to perform work in the workshop, various tools, instruments and equipment are used. Some of these instruments found in an electrical workshop are:
         i.            Ammeters,
       ii.            Ohmmeters ,
      iii.            Voltmeters,
     iv.            oscilloscopes ,
       v.            Power packs

During the storage of such instruments, safety precautions and procedures have to be followed to avoid damage. If poorly stored or handled the instruments may:
a)      give false readings when in use,
b)      be damaged by water and dampness,
c)       give an electric shock due to dampness,
d)      be damaged when Incorrectly connected.

The following are some points to remember when storing and handling such instruments:
a)      Always store them in a dry, cool place.
b)      Never stack instruments and tools one on top of each other.
c)       Never drop them.
d)      Never switch on power sources before checking the circuit.

Other equipment found in the workshop include:
         i.            drill press,
       ii.            bench grinders,
      iii.            lathe machines.

These machines and equipment are dangerous mainly because of their moving parts. Careless use of these machines can cause a severe injury to the body and sometimes maim the user. It is, therefore, very important to know how to:
1.       start a particular machine,
2.       operate it safely,
3.       stop it.

When using electrically powered tools or equipment, the following safety procedures should be significantly observed:
1.       Do not let loose cables obstruct other workshop users.
2.       Make sure that all electrical connections are safe.
3.       Never switch on an electric source if others are leaning on the equipment.
4.       Always use protective gear such as a face shield, goggles and gloves when welding.
5.       Keep inflammable materials away when using electrical equipment.
6.       Do not use these electrical equipment in damp areas.
7.       Electrical equipment with metal bodies must always be earthed.
8.       Always remove the plug from the socket outlet when the equipment is not in use.

After use of any of the above mentioned and similar equipment, the power supply cables should be folded carefully. Equipment must also be stored in a safe area in the electrical workshop or in the store where they do not cause an obstruction.
In one sentence, always exercise safety when storing and handling tools, materials, instruments and equipment.

Storage and Handling of Materials

Storage and Handling of Materials

Materials used in the workshop may be classified as:
a)      corrosive,
b)      combustible or,
c)       non-combustible materials.
When dealing with any of these materials, care must be taken to avoid accidents associated with them.

Examples of corrosive materials are:
         i.            Sulphuric acid,
       ii.            Killed spirits such as zinc chloride acid,
      iii.            Hydrochloric acid.

All acids must be treated as dangerous and should be stored and handled very cautiously. For instance, sulphuric acid causes painful and serious burns if it gets on the skin and, as such, proper protective clothes such as gloves and aprons must always be worn when working with acids. To avoid explosions during mixing, always add acid to water and not vice versa.
Other materials regularly used in the workshop are highly flammable or combustible. They are:
         i.            petrol,
       ii.            kerosene,
      iii.            methylated spirit.

These should be stored and handled very carefully so that accidental fires are avoided. They should be stored in clearly labelled containers and possibly with warnings. Fires from them are fierce and may cause severe burns or death to many people. Besides, a fire can destroy the whole workshop, including expensive equipment, the tools housed in the building and the building too!

Other materials used in an electrical shop, although less flammable, must be protected from high temperatures. Electric cables insulating materials such as rubber and polyvinyl chloride (P.V.C.) will easily be destroyed by fire. When working on cables and wires using a naked flame, safety precautions must always be taken.

Materials such as metal bars, pipes, tube and asbestos which are heavy and sometimes long can pose danger to people when stored or handled carelessly. The storage of these materials must be done in such a way that they do not obstruct gangways. Asbestos, though non-combustible, must be handled with great care since inhaling asbestos may cause lung cancer. Asbestos, must, hence, be treated as a very dangerous material.
When using any material, always be sure of the safe method of handling it.  There are dangers associated with the way some materials are heated or used. Knowledge of the behaviours or characteristics of various materials under different conditions of use and storage is essential in order to handle them without harm.

Storage and Handling of Tools

Storage and Handling of Tools

Tools are of many forms and sizes and, when stored and handled carelessly, can easily cause accidents. To avoid this, storage facilities must be provided in the electrical workshop. Tools may be stored in:
a. tool box
b. tool kit,
c. tool rack.

For easy identification, simple sketches of the tools may be painted in the storage facilities. This is called shadow-painting.

Shadow-painting
a. eases and quickens the process of returning the tools in their proper places.
b. speeds up the checking of tools

Some common methods of tools storage systems are as shown:

Trolley

Box

Rack or Wallboard

Shadow painting in use

Storage of Tools, Materials and Equipment

1.4 Storage of Tools, Material and Equipment

Overview

Tools, materials and equipment in the workshop must be handled and stored carefully to a manner that does not create a risk to the safety or health of a worker or affect the safe operation of the workshop.
Accidents may cause injuries (sometimes fatal) or damage tools, materials and equipment. Therefore, it is very important to think of safety when handling these items.
General  procedures must be provided as step by step guidance on how to manage each aspect of category and may cover:

1. receipts and issues of tools, materials and equipment
2. quality control or verification
3. proper storage control
4. how to control stock movement safely of tools, materials and equipment
5. documentation flow to track users
6. how to detect and deal with stock losses of tools, materials and equipment
7. how unwanted tools, materials and equipment should be handled

Personal Movement and Conduct in an electrical workshop

1.3 Personal Movement and Conduct

Students need to realize electricity workshops have their own safety rules that students may not have met in some other places. These rules should be distinct from the normal schools.  For instance, a class may be locked for fear of theft whereas in an electrical work safety may be overrule!
Accidents are preventable and therefore all the learners and the teacher instructor must work together.  To do this always observe the following:

1. Never horse-play in the electrical workshop;
2. Always alert others when carrying long or sharp objects;
3. Seek assistance, if you have to carry heavy objects;
4. Never stand or lie under heavy objects suspended above the ground;
5. Do not walk blindly. Please always look where you are going;
6. Keep workbenches and machine tops clean and tidy;
7. Always wipe spilt oil, grease or water off the floor immediately;
8. Never leave a running machine unattended;
9. Wash hands immediately after work;
10. Avoid taking meals or drinking in the electrical work

Class Activity
a. Go look at electrical workshop and draw its layout. 
b. Circle and label areas where you notice a good safety practice. 
c. Use a highlighter to mark any places with safety hazards. 
d. List the safety hazards you may think can  occur.


Quote
The best way of doing something is always the safest one!

Personal Dressing Safety Video

Personal Dressing Safety

1.2 Personal dressing

In an electrical workshop, it is always important to be properly dressed. This will provide protection from dangers associated with electricity, moving machine parts, tools and materials. The following dressing is therefore suggested:

Shoes

Should provide a good rubber grip on the floor and be of suitable top and, if possible, reinforced with steel toecaps to protect the feet against injuries from sharp and heavy objects.

Clothing

Should be either an overall, a dustcoat or an apron worn to protect the body and personal clothing. They should be short-sleeved; long sleeves should be rolled or buttoned up. All buttons should be in place and done up. Neckties should be removed or tucked-in, especially when working with machines, else they might be caught up in the moving parts.

Hand Gloves

Rubber, plastic or leather gloves should be worn when handling acids, other corrosive substances, as well as hot objects.

Helmets

These should be worn in areas where there is danger from falling objects. They can also help in controlling loose hair when operating machines. Long, loose hair should be trimmed or tied.

Safety Goggles

These are eye protective devices made of clear plastic. They are worn to protect the eyes from flying particles when drilling, cutting, grinding, milling and doing lathe work.

Face Shield

This is a device capable of blocking sparks and excessive light and heal from reaching the face. It must be worn when brazing or welding to protect the eyes from permanent damage and the face from serious burns.                                        

Bangles, Rings and Necklaces

These items should not be worn while working in the electrical workshop; otherwise they might be caught by the revolving parts of machines and even cause injuries. If made of metal, they also apt to conduct heat or electricity to the body when in contact with the source.

Personal Dressing Safety Video

General safety rules at school

1.0             Introduction

We are all mandated to ensure that the place in which we work is free from dangers associated with electricity, machines, materials and the tools we use. We cannot confidently perform our duties if we know that we are not safe. Therefore, this implies that we are all managers not only committed to support safety, but we must insist on electricity safety rules at school performance in a manner that is clearly understood and echoed at all cadres of life.

1.1       General Safety Rules

Accidents do not just occur; they are caused. To prevent them, always:
1. think before you act; if you are not certain please seek assistance;
2. concentrate on your work;
3. be mindful of your safety and the safety of others;
4. dress properly for the job to be done;
5. poise properly when carrying out a particular activity;
6. no horse-playing around in the place of work;
7. use the correct tools and machines for their intended job.
8. wear goggles, a face shield, gloves or some other safety device when you go around machines such as grinders or welders or when handling chemicals;
9. use only portable electrical equipment that have adequate earth connections. An earth connection is a protective wire that connects the metal frame of the portable electrical device with the earth wire.

A bad workman quarrels with his tools.